In modern day, in the city of Verona Beach, the Capulets and the Montagues are rivals. The animosity of the older generation – Fulgencio (Paul Sorvino) and Gloria Capulet (Diane Venora) and Ted (Brian Dennehy) and Caroline Montague (Christina Pickles) – is felt by their younger relatives. While stopping for gas, the Montague boys led by Benvolio (Dash Mihok), Romeo’s cousin, come face to face with the Capulet boys led by Tybalt (John Leguizamo), Juliet’s cousin. A gunfight ensues between Benvolio and Tybalt, setting fire to the petrol station and creating chaos in the city. The Chief of Police, Captain Prince (Vondie Curtis-Hall), reprimands the boys, as well as Fulgencio and Ted. He warns them that if such behavior continues, their lives “shall pay the forfeit of the peace”.
Caroline expresses her worry over her son, Romeo (Leonardo DiCaprio), who has been depressed. Benvolio talks to his cousin and learns that Romeo is in love, but the object of his affection, Rosaline, does not love him. Dave Paris (Paul Rudd), son of the Governor and nominated “Bachelor of the Year”, meets with Fulgencio. Paris wants to marry Fulgencio’s daughter, Juliet (Claire Danes), but Fulgencio thinks she is too young. Nevertheless, he invites Paris to a party he is hosting that night. Gloria tries convincing Juliet to accept Paris’ proposal, but she is not persuaded. Meanwhile, at Sycamore Grove, the Montague boys and Romeo meet their friend, Mercutio (Harold Perrineau), who has gotten them tickets to the Capulet party. Mercutio tries convincing Romeo to attend the party, which Rosaline will also be attending. Romeo takes a pill Mercutio gives him, and they proceed to the Capulet mansion. The effects of the drug and the party overwhelm Romeo, who goes to the restroom. While admiring the fish tank, he spots Juliet on the other side. Before they can speak, Juliet’s nurse (Miriam Margolyes) whisks her off to dance with Paris. Romeo is spotted by Tybalt, who vows to kill him for invading his family’s home, but Fulgencio stops him, afraid he will make a scene. Romeo and Juliet sneak into an elevator and kiss, but are spotted by the nurse when the doors open. Juliet is dragged away by her nurse, who reveals Romeo’s identity as a Montague at the same time Romeo realises Juliet is a Capulet. Romeo is pulled from the party by Mercutio while Juliet watches from a balcony.
Romeo sneaks back to the mansion, hiding under Juliet’s balcony. Juliet emerges into the yard, not knowing he is there, and proclaims her love for him before Romeo sneaks up behind her. Juliet is horrified that he risked death to return, but Romeo tells her he does not care whether he is caught. Knowing her nurse is looking for her, Juliet tells him that if he sends word by the following day, she will be his. Romeo visits Father Lawrence (Pete Postlethwaite), telling him he wants to marry Juliet. The priest agrees to marry the pair. Romeo passes the word onto Juliet’s nurse, and the lovers are married that afternoon, with the nurse and Romeo’s friend Balthasar (Jesse Bradford) as witnesses. Tybalt encounters Mercutio and the Montagues. As the two are about to draw their weapons, Romeo arrives. He attempts to make peace, but Tybalt assaults him. Mercutio is about to kill Tybalt when Romeo stops him. Tybalt stabs Mercutio with a shard of glass, killing him, but not before Mercutio curses the warring houses. Romeo kills the fleeing Tybalt. Prince banishes Romeo from the city on pain of death. Romeo, hiding with Father Lawrence, claims he would rather die than be banished. At the Capulet mansion Juliet prays, horrified by what has happened. When Romeo climbs over her balcony, she kisses him and they make love. Fulgencio decides Juliet will marry Paris.
The next morning, Romeo prepares to leave as Juliet begs him to stay. Juliet’s nurse tells them Gloria is on her way to Juliet’s room. Romeo climbs out the window, promising Juliet he will see her again. Juliet learns she has been promised to Paris. When she refuses to marry Paris, her father tells her that if she does not marry Paris she will be disowned and thrown onto the streets. Her mother refuses to delay the wedding and her nurse tells her it would be in her best interests to marry Paris. Faced with the possibility of being wedded to Paris, Juliet sees Friar Lawrence, imploring him to help her and threatening to commit suicide. The priest proposes she fake death instead, so she will be put in the Capulet vault to awaken 24 hours later. Romeo will be told of the plot, sneak into the vault, and once reunited, the two can travel to Mantua. He gives her the poison necessary to make her seem dead.
After saying goodnight to her mother, Juliet takes the poison. She is found in the morning, declared dead, and placed in the Capulet vault. Balthasar learns Juliet is dead and tells Romeo, who was not home when the messenger arrived to tell him of the plan. Romeo returns to Verona, where he buys poison. Father Lawrence learns that Romeo has no idea Juliet is alive. Romeo enters the church where Juliet lies. Juliet awakens as Romeo drinks the potion. The two kiss before Romeo dies. Juliet picks up Romeo’s handgun and shoots herself in the head. The two lovers are discovered in each other’s arms.
The film ends with ambulances coming and a crowd assembles as Captain Prince shames everyone for the events that occurred.